| Abstract: | The Custer graben is a 13 by 32 km northeast-trending volcano-tectonic graben in the Challis volcanic field of central Idaho. Andesites, rhyolites, and associated pyroclastic rocks host vein and disseminated gold-silver deposits that are localized along discrete northeast- and northwest-trending fracture zones. Ore minerals in vein deposits are electrum, native gold and silver, chalcopyrite, and various sulfosalts in a gangue of pyrite and fine-grained quartz. At the Sunbeam Mine, near the center of the graben, vein and disseminated gold-silver mineralization occurred in hydrothermally altered rhyolite and pyroclastic rocks. The host rock has been pervasively silicified, and the feldspars altered to clay minerals. Analyses of surface and drill-core samples show that altered rocks are variably enriched in gold, silver, molybdenum, arsenic, zirconium, and selenium. Intense silicification is shown by SiO//2 values at high as 93%. |
| Genre: | Article |
| ProdID: | 70014012 |
| Citation Author: | Johnson, Kathleen, M.; McIntyre, David, H. |
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| Citation End Page: | 248 |
| Citation Issue: | 1-2 |
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| Citation Language: | English |
| Citation Larger Work Title: | Journal of Geochemical Exploration |
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| Citation Number Of Pages: | 2 |
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| Citation Search Results Text: | EPITHERMAL GOLD-SILVER MINERALIZATION RELATED TO VOLCANIC SUBSIDENCE IN THE CUSTER GRABEN, CUSTER COUNTY, IDAHO.; 1984; Article; Journal; Journal of Geochemical Exploration; Johnson, Kathleen, M.; McIntyre, David, H. |
| Citation Start Page: | 247 |
| Citation Volume: | 25 |
| Citation Year: | 1984 |
| Type: | citation/reference |
| Text: | EPITHERMAL GOLD-SILVER MINERALIZATION RELATED TO VOLCANIC SUBSIDENCE IN THE CUSTER GRABEN, CUSTER COUNTY, IDAHO.; 1984; Article; Journal; Journal of Geochemical Exploration; Johnson, Kathleen, M.; McIntyre, David, H. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Sun, 1 Jan 1984 00:00 -0600 |
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